Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK rnm30@medschl.cam.ac.uk.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

THIS (The Healthcare Improvement Studies) Institute, University of Cambridge, Cambridge, UK.

THIS (The Healthcare Improvement Studies) Institute, University of Cambridge, Cambridge, UK.

THIS (The Healthcare Improvement Studies) Institute, University of Cambridge, Cambridge, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Bristol Medical School, University of Bristol, Bristol, UK.

Heart Arrhythmia Alliance, Chipping Norton, UK.

Primary Care Population Sciences and Medical Education, University of Southampton School, Southampton, UK.

Department of Health Sciences, George Davies Centre, University of Leicester, Leicester, UK.

Bristol Medical School, University of Bristol, Bristol, UK.

Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, Liverpool, UK.

Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.

Department of Health Sciences, George Davies Centre, University of Leicester, Leicester, UK.

Guy’s & St Thomas’ NHS Foundation Trust, Royal Brompton Hospital, London, UK.

Faculty of Life Sciences and Medicine, Kings College London, London, UK.

Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London, UK.

Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK.

Heart research Institute, Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

MRC Epidemiology Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.

Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.

Strangeways Research Laboratory, Primary Care Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.